Homogeneous growth of antidot structures electrodeposited on Si by nanosphere lithography

The characteristics of cobalt antidot structures, electrodeposited on Si by nanosphere lithography, is investigated by analysis of current transients and optical and atomic force microscopy. Polystyrene colloidal masks of 1 ML (monolayer) or a maximum of 2, with sphere diameters ranging between 165 and 600 nm were fabricated by spin coating. For masks partially covered with bilayer regions, it is shown that the volume of deposited material in bilayer areas corresponds to only 5% of the cobalt deposited in the monolayer areas. This drastic reduction in the deposition rate affects the quality of the deposit. Therefore, the use of colloidal masks of homogeneous thickness is necessary to guarantee the electrodeposition of nanostructured films of controlled thickness. It will also be shown that the use of high quality colloidal masks yields a reproducible electrodeposition process, enabling the use of the current transient as a reliable tool for assessment of the deposition process.